A beam clamp refers to a clamp that is clamped, such as, on a beam in a workshop. The existing beam clamp usually adopts two claws to clamp edges at the two sides of a beam body, and uses bolts to fasten the claw positions, thus fixing the beam clamp on the beam, and then being capable of realizing other support and fixation effects through the clamp. However, this clamp requires that the edges at the two sides of the beam shall be provided with edge for clamping, for example, an “I” beam, and cannot be applied to a beam only having a single-side protruded edge. Therefore, it needs a better beam clamp structure which not only can realize single-side clamping and fixation, but also can ensure to provide enough support strength, and can bear weight during long-term high-load application.